Electromagnetic touch panel is an input device using electromagnetic technology. The electromagnetic touch panel is used with a special electromagnetic pen. When the electromagnetic pen is written on a touch surface of the electromagnetic touch panel, the electromagnetic pen can emit electromagnetic signals with special frequencies, and the electromagnetic touch panel can calculate a coordinate of the electromagnetic pen according to the electromagnetic signals. Moreover, the electromagnetic pens can be classified as active electromagnetic pens and passive electromagnetic pens. The active electromagnetic pen needs a battery to supply power, and the passive electromagnetic pen does not need the battery to supply power. Compared with the electromagnetic touch panel using the passive electromagnetic pen, the electromagnetic touch panel using the active electromagnetic pen does not need to emit energy for the electromagnetic pen. Therefore, the electromagnetic touch panel using the active electromagnetic pen has advantages of power saving and high report rate of coordinate information.
FIG. 1 is a schematic view of a conventional active electromagnetic pen. Referring to FIG. 1, a conventional active electromagnetic pen 100 includes a pen body 110, a pen tip 120, a pressure detecting module 130 and a power supply module 140. The pen body 110 has an opening 112 on one end thereof, and the pen tip 120 is disposed at the opening 112 of the pen body 110. The pen tip 120 has a tip end 122 and a plane end 124 opposite to the tip end 122. The plane end 124 is disposed in the pen body 110, and the tip end 122 is extended to outside of the pen body 110 through the opening 112. The pressure detecting module 130 is disposed in the pen body 110, and the pressure detecting module 130 has a pressure detecting element 132. The pressure detecting element 132 is connected to the plane end 124 of the pen tip 120 via a connecting element 134. The power supply module 140 is disposed in the pen body 110 and is configured to supply power to the pressure detecting module 130.
When the pen tip 120 is pressed by external force, the pressure detecting element 132 can detect the pressure, and the pressure detecting module 130 can send the detected pressure values via emitting electromagnetic signals with special frequencies, and the electromagnetic touch panel can calculate the coordinate of the active electromagnetic pen 100 according to the received electromagnetic signals.
However, in the conventional technology, since the pressure detecting module 130 includes only one pressure detecting element 132, detecting sensitivity is low. Furthermore, the direction of pressure applying on the pen tip 120 can not be detected.